What happened
The aircraft departed and climbed to a cruise altitude of 7,000 feet. Approximately 15 minutes into the flight, the engine began to cut in and out. The pilot was unable to maintain engine operation and subsequently performed a forced landing off the airport into rising terrain. There were no injuries reported.
The investigation
An examination of the aircraft revealed rust on the underside of the right main fuel tank cap. Additionally, a co-owner acknowledged that the right main fuel tank would occasionally contain water. Prior to the arrival of the FAA, the fire department had foamed and emptied the fuel tanks.
A post-accident inspection of the engine identified rust-colored water within the carburetor bowl and in the fuel line leading to the carburetor. After the water was removed and cleaned out, the engine was tested and ran satisfactorily.